Topologically-protected single-photon sources with topological slow light photonic crystal waveguides

TL;DR

This paper demonstrates topologically-protected slow light waveguides embedded with quantum dots, enabling robust, high-efficiency single-photon emission suitable for scalable quantum photonic circuits.

Contribution

It introduces a novel topological slow light waveguide platform with embedded quantum dots for robust single-photon sources, overcoming propagation loss issues.

Findings

Purcell-enhanced single-photon emission observed

Group index over 20 achieved in topological waveguides

Robust propagation maintained despite sharp bends

Abstract

Slow light waveguides are advantageous for implementing high-performance single-photon sources required for scalable operation of integrated quantum photonic circuits (IQPCs), though such waveguides are known to suffer from propagation loss due to backscattering. A way to overcome the drawback is to use topological photonics, in which robust waveguiding in topologically-protected optical modes has recently been demonstrated. Here, we report single-photon sources using single quantum dots (QDs) embedded in topological slow light waveguides based on valley photonic crystals. We observe Purcell-enhanced single-photon emission from a QD into a topological slow light mode with a group index over 20 and its robust propagation even under the presence of sharp bends. These results pave the way for the realization of robust and high-performance single-photon sources indispensable for IQPCs.